• Journal of Sericultural and Entomological Science
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• v.50 no.1
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• pp.10-14
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• 2012

Resveratrol is naturally occurring phytoalexin compounds produced by grape berries, peanuts, pine tree, mulberry fruits and their products in response to stress such as fungal infection, heavy metal ions or UV irradiation. The objective of this study was to determine resveratrol contents in wild-type mulberry leaves (Morus alba L., M. bombycis Koidz, and M. Lhou (Ser.) Koidz) collected from Won-ju, In-je and Yang-yang regions, Gangwon province, Korea. Resveratrol contents in wild-type mulberry leaves were higher in Autumn's than in Spring's, and higher than 16 cultivar's. Among the samples, 'No. 3', collected from Won-ju region and 'No. 7' collected from In-je showed high resveratrol contents of 539 and $491{\mu}g$/100 g DW (dry weight; DW), respectively, through the collection time. Therefore, two mulberry trees might be promising as potent resources for mulberry breeding and functional material development.

• Korean Journal of Breeding Science
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• v.43 no.2
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• pp.145-153
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• 2011

To develop new varieties of rapeseed (Brassica napus L.), the seeds of three varieties 'Naehan', 'Tammi', and 'Halla' were treated with proton ion beams and gamma rays (0~2,000 Gy), and then the characteristics of the mutants induced were examined up to $M_5$ generation to select the lines with fixed useful traits. In $M_5$ generation, we had selected several lines that were highly fixed for some useful traits such as plant height, maturity and flower size; one line with both earlier maturity and shorter stem than wild type, one line with only earlier maturity, two lines with shorter stem, one line with large flower, and one line with chlorophyll mutation. Among them, NP600-1-1-198-2 (induced from variety 'Naehan' was treated with proton ion beams 600 Gy) was superior for its distinction from the original variety, uniformity and stability. The unique characteristics of NP600-1-1-198-2 were dark green leaves, green stem, yellow flower, and black seed coat. Its flowering date was April 14, eight days earlier than its original variety, while seed maturity date was June 16 (five days earlier) and plant height 105 cm (shorter by 10 cm). NP600-1-1-198-2 has 52 silique per panicle, 6.2 cm silique length, 23 seeds per silique, 4.2 g per 1000 seeds and 45.9% oil content. The seed oil contained 67.8% of oleic acid, 16.7% of linoleic acid and 7.3% of linolenic acid but no erucic acid.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.303-307
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• 2008

We bred a new green-kerneled glutinous rice variety that can be cultivated in the whole area of Korea, because only one native green-kerneled glutinous rice cultivar, "Saengdongchalbyeo", has been cultivated in the southern coastal area due to its late heading. The seeds of "Saengdongchalbyeo" were irradiated with 200 Gy of gamma ray in 1995. A promising mutant variety, "Nogwonchalbyeo" ("Wonnong 17") was selected through line selection and regional yield trials. In particular, the new variety revealed at the earlier mid of August compared to that of "Saengdongchalbyeo", the early of September, and it was considerably tolerant to a field lodging due to its shortened culm length. Also, "Nogwonchalbyeo" had a higher ripened grain ratio and 1,000 grain weight compared to the original variety. The brown grain yield of the new variety was about 5.40 MT/ha, which was 11.3% higher than that of the original variety, in the regional yield trials at 3 different fields during 2000~2001. The brown and milled grains of the new rice variety contained 20 to 65% higher amount of total amino acids, respectively than that of the original and two checks. For chlorophyll -a, -b and total chlorophyll, the new variety showed nearly two-fold higher than the checks, and for the carotenoid, it had 5.3 - 7.6 times higher amount. These results showed that the new variety can be cultivated as a special green-kerneled glutinous rice with high functional compounds.

• Journal of Microbiology and Biotechnology
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• v.33 no.6
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• pp.831-839
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• 2023

Tylosin is a potent veterinary macrolide antibiotic produced by the fermentation of Streptomyces fradiae; however, it is necessary to modify S. fradiae strains to improve tylosin production. In this study, we established a high-throughput, 24-well plate screening method for identifying S. fradiae strains that produce increased yields of tylosin. Additionally, we constructed mutant libraries of S. fradiae via ultraviolet (UV) irradiation and/or sodium nitrite mutagenesis. A primary screening of the libraries in 24-well plates and UV spectrophotometry identified S. fradiae mutants producing increased yields of tylosin. Mutants with tylosin yield 10% higher than the wild-type strain were inoculated into shake flasks, and the tylosin concentrations produced were determined by high-performance liquid chromatography (HPLC). Joint (UV irradiation and sodium nitrite) mutagenesis resulted in higher yields of mutants with enhanced tylosin production. Finally, 10 mutants showing higher tylosin yield were re-screened in shake flasks. The yield of tylosin A by strains UN-C183 (6767.64 ± 82.43 ㎍/ml) and UN-C137 (6889.72 ± 70.25 ㎍/ml) was significantly higher than that of the wild-type strain (6617.99 ± 22.67 ㎍/ml). These mutant strains will form the basis for further strain breeding in tylosin production.

• Mycobiology
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• v.32 no.2
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• pp.88-94
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• 2004

Protoplasts of the wild type strain of Pleurotus osteatus were mutagenized with UV light, and 3,000 colonies were examined for abnormal mycelial and fruiting phenotypes. Forty one strains displayed variant phenotypes in mycelia and fruiting processes. The variant phenotypes were classified into 6 groups: (1) auxotrophic strains, which are incapable of growing on minimal media and can only grow when provided with their specific requirements; (2) abnormal vegetative strains, which grow very slowly on minimal and complete media; (3) primordiumless strains, which fail to develop to the formation of primordia; (4) maturationless strains, which form primordia, but do not form mature fruiting bodies; (5) specifically colored strains, which have Specific bluish grey or bluish white pileus; (6) poorly spored strains, which fail to produce basidiospore or which produce few spores. These variant strains may be useful in genetic breeding programs and for the studies of fungal development and genetics.

• Korean Journal of Plant Tissue Culture
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• v.27 no.2
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• pp.143-148
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• 2000

This study was carried out to know the optimum dose of gamma-ray for the induction of mutation in vitro and the characteristics of the mutants induced by gamma-ray in persimmon (Diospyros kaki Thunb.). The LD50 (50% lethal dose) for in vitro shoots of the cultivar, Nishimurawase was between 1 krad and 2 krad and about 1 krad for the cultivar, Ichikikeijiro. As the dose of gamma-ray increased, the length of shoots decreased and necrosis of buds increased. For the cultivar, Nishmurawase, 37.5∼58.3% shoots rooted and the rooting rate and the number of roots per shoot was low in high gamma-ray. The irradiated young plants which were grown in the growth cabinet for 6 weeks were shorter in shoot length and had more branches than non-irradiated plants. The survival rate of irradiated plants grown in the green house for 3 months was 33%, while 77% for control plants.

• Korean Journal of Breeding Science
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• v.49 no.3
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• pp.150-156
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• 2017

This study was carried out to compare the survival and mutation rates and mutation spectrum by gamma-irradiation on rooted and unrooted cuttings of three spray type ('Lovelydia', 'Yellowbabe', and 'Haetsal') and two standard type ('Vital' and 'Aqua') cultivars in roses. Two groups, rooted and unrooted cuttings were gamma-irradiated at 70Gy for 24 hours. The irradiated rooted and unrooted cuttings were planted in a greenhouse, and survival, mutation rates and mutation spectrum were investigated 30 weeks after planting, respectively. As a result, survival and mutation rates of gamma-ray irradiated plants were 16.4%~50.8% and 0~5.1% for unrooted cuttings, and 39.4%~55.1% and 0.7%~7.4% for rooted cuttings, respectively. In conclusion, both survival and mutation rates were a little higher on rooted cuttings than on unrooted cuttings. However, when only survived plants after gamma-ray irradiation were considered, mutation rates were 0~10% and 1.8%~14.1% for unrooted cuttings and rooted cuttings, respectively, showing no significant difference. In addition, diverse variations on color and number of petals or shape of flowers were detected both in plants from rooted and unrooted cuttings, which indicated that there was no significant difference in mutation spectrum between two groups.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.348-353
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• 1996

Mutation tachniques inducing more useful mutations and reducing somatic effects need to be improved for crop breeding. Seeds of barley varieties ; Dema, Grosso were treated with two types of mutagens ; 1) chemical treatment: single treatment or double treatment of two mutagens (N-nitroso-N-methylurea ; MNH, Sodium Azide; NaN$_3$) 2) gamma ray irradiation treatment. After treatment, half of seeds were used for germination test and half of seeds were sown to the field. With the higher dose of mutagen both chemical and gamma ray were plants treated, the higher rate of growth reduction rate was in M$_1$ seedling. In chemical treatment, germination rate of seeds, growth rate of coleoptile and root in double treatment of chemical mutagens were better than single treatments, especially in same dose. Growth inhibition rate of plant in double treatment of 1.0mM MNH(0.5mM MNH + 0.5mM MNH), for example, were less than one of plants of single treatment of 1.0mM MNH in pot and petri dish test. Growth reduction rate of culm and fertility rate in M$_1$ plants double treated in same dose of single treatment were also less than single one. With the higher dose of mutagen both chemical and gamma ray were plants treated, the higher frequency of chlorophyll mutants was in M$_2$ seedling. The rate of chlorophyll mutants in double treatment of chemical mutagens were higher than single treatment. Double treatment methods can be a improved method for induction of new good mutants, which were induced more useful mutations and reduced harmful somatic effects.

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.181-186
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• 2008

To assess the potential as biofortified rice varieties, new endosperm and grain mutant lines were selected from $M_4$ generation seeds of the rice cultivar Shindongjin, which were either $\gamma$-irradiated or treated with N-methyl-N-nitrosourea(MNU) and lipid, sugar, and tocopherol content were analyzed. Amylose content in non-waxy mutants ranged from 8.8% in SM-4, a dull-type mutant, to 29.5% in SM-51, compared to 18.9% in the parental variety, Shindongjin. SM-23, a floury-type mutant, contained 0.09 ${\mu}g/g$ $\alpha$-tocopherol(40.9% of total tocopherol), was three times higher than in the parental variety. SM-32, a giant embryo-type mutant, had a 2.2-fold higher total tocopherol content, 2.1-fold higher $\alpha$-tocopherol, and 5.5-fold higher $\delta$-tocopherol content(47.3% of total tocopherol) than the parental variety(0.13 ${\mu}g/g$). Total free sugar content was elevated in all selected mutants and 1.2-8.6 times higher than in the parental variety(11.38 ${\mu}g/g$). These increased sugar levels were due to increase in sucrose concentration. SM-23(floury-type mutant) and SM-51(high amylose-type mutant) had 4.6 and 7.0 times more sugar, respectively, than the parental variety(11.38 ${\mu}g/g$). With relatively high concentrations, most mutants showed elevated fatty acid content in the SM 32(giant embryo-type) and SM-51(high amylose-type) mutants, at 124.56 and 89.59 mg/g, respectively. All selected mutants displayed valuable characteristics for the development of new varieties in rice-breeding programs.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.240-240
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• 2017

Quinoa (Chenopodium quinoa Willd.) is one of the ancient crops cultivated in the Andes region at an altitude of 3,500-4000m in Chile and Bolivia from 5000 BC. It contains a large amount of protein, minerals and vitamins in comparison with other crops. The cultivation area has been increasing worldwide because of its excellent resistance to various abiotic stress such as salinity, drought and low temperature. ${\gamma}$-Ray radiation of high dose is often used as a tool to induce mutations in plant breeding, but it has a deleterious effect on organisms. However, the radiation may have a positive stimulatory effect of 'hormesis' in the low dose range. This experiment was carried out to investigate the optimum dose range for creating the quinoa genetic resources and to investigate the hormesis effect at low dose on the quinoa. This experiment was performed for 120 days from November, 2016 to February, 2017 in the greenhouse of Gyeongsang National University. ${\gamma}$-Ray radiation was irradiated to seeds at 0 Gy, 50 Gy, 100 Gy, 200 Gy, 300 Gy, 400 Gy, 600 Gy, 800 Gy and 1000 Gy for 8 hours. (50 Gy) using the low level radiation facility ($Co^{60}$) of Cooperative Research Institute of Radiation Research Institute, KAERI. Fifty seeds were placed on each petri dish lined with wet filter paper and germination rate was measured at a time interval of 2 hours for 40 hrs. The length of the root length was measured one week after germination. Each treatment was carried out in 3 replicates. The growth of seedlings were investigated for 10 days after transplanting of 30 day-old seedlings. The plant height, NDVI, SPAD, Fv/Fm, and panicle weight were measured. The germination rate was highest at 50Gy and 0Gy and the rate of seeds treated with 400Gy or higher rate decreased to 25% of the seeds treated with 50Gy. The emergence rate of seedling in pot experiment was higher at the dose of 200 Gy, 300 Gy and 400 Gy than at 0 and 50Gy. However, the rate was lower at strong radiation higher than 600Gy at which $1^{st}$ leaf was not expanded fully and dead due to extreme overgrowth at 44 days after treatment (DAT). The highest value of panicle weight was observed at 50Gy (6.15g) and 100Gy (5.57g). On the other hand, the weight at high irradiated dose of 300Gy and 400Gy was decreased by about 55% compared to low dose (50 Gy). NDVI measurement also showed the highest value at 50 Gy as the growth progressed. SPAD was the highest at 400 Gy and showed positive correlation with irradiation dose except 0 Gy. Fv/Fm was high at 50 Gy up to 30 DAT and no difference between treatments was observed except for 400 Gy from 44 DAT. The plant height was the highest in 50Gy during the growing period and was higher in the order of 50Dy, 100Gy, 0Gy, 200Gy, 300Gy and 400Gy in 88 DAT. In this experiment, the optimal radiation dose for hormesis was 50Gy and 100Gy, and the optimal radiation dose for mutagenesis seems to be 400 Gy.